Gibbons Sing Like Human Sopranos When Dosed With Helium

Singing gibbons use the same vocal techniques as soprano singers
when calling to one another across the jungle, a study has found.

Humans were believed to have evolved our unique speaking ability
through an evolutionary change in our anatomy, but an analysis of
how gibbons sing under the effects of helium gas suggests
otherwise.

The study by Japanese scientists demonstrates that Gibbons share
the same vocal structure as humans, indicating that humans have
simply learned to use our voices in a more complex way.

In their songs, gibbons use the same difficult vocal technique
that soprano singers learn which allows them to put more power
behind higher notes than lower ones, the researchers found.

Dr Takeshi Nishimura, who led the study, said: "This is the first
evidence that gibbons always sing using soprano techniques, a
difficult vocalisation ability for humans which is only mastered
by professional opera singers.

"This gives us a new appreciation of the evolution of speech in
gibbons while revealing that the physiological foundation in
human speech is not so unique."

Gibbons use their songs to communicate with neighbours and
potential mates across up to two miles of jungle, producing a
loud melody which is acoustically different to other primates.

Researchers from Kyoto University recorded 20 calls made by
gibbons in a zoo, and compared them with 37 calls made when the
animals had breathed in helium.

The gas makes voices appear high-pitched and squeaky by altering
the way our vocal tract processes the sounds we produce.

In normal air the lowest frequencies of a gibbon's song are the
loudest, but under the effect of helium the tuning of their vocal
cords and resonance of the vocal tract changed to amplify higher
frequencies.

The results showed that gibbons are capable of consciously
manipulating their vocal chords to make their signature calls,
the researchers explained in the American Journal of Physical
Anthropology.

This suggests gibbons produce sounds in the larynx but use a
filter to manipulate them, in the same way humans craft basic
sounds into speech.